Discrete element method parameter calibration and validation of wheat based on the Tavares model.

Area of Science:

• Agricultural Engineering
• Material Science
• Computational Mechanics

Background:

• Existing discrete element models for wheat lack accuracy due to simplified fracture behavior and uncalibrated parameters.
• Wheat grain anisotropy significantly impacts fracture mechanics, necessitating advanced modeling approaches.

Purpose of the Study:

• To systematically calibrate and validate contact and crushing parameters for wheat grains using the Tavares crushing model.
• To develop an anisotropic wheat compression-fracture simulation model for roller milling applications.

Main Methods:

• Combined physical experiments (uniaxial compression, drop hammer impact, angle of repose) with discrete element simulations.
• Determined contact parameters (friction, restitution) between wheat grains and white cast iron, and wheat-wheat.
• Calibrated fracture energy distribution and cumulative damage coefficient for the Tavares model.

Main Results:

• Validated contact parameters using angle of repose tests with a 1.05% deviation.
• Fracture energy follows a log-normal distribution (median 2069.78 J/kg), with a calibrated cumulative damage coefficient of 5.
• Simulated compression force-displacement curves showed low relative errors (4.47% for force, 1.27% for energy).

Conclusions:

• The calibrated Tavares model accurately simulates anisotropic wheat grain fracture.
• Provides a validated simulation tool for optimizing wheat roller milling processes.
• Offers significant value for improving wheat processing quality and efficiency.